Computer systems, for example, desktop computers, personal digital assistants, laptop computers, tablet computers, and the like, are configured to implement computer software applications by executing computer program instructions to perform operations. Mobile computer systems, which are sometimes known as mobile devices, are portable versions of computer systems, and can also implement computer software applications, which, in some situations, are designed specifically for mobile devices. For example, many Internet publishers offer a version of an electronic mail (e-mail) application for computer systems, such as, desktop and laptop computer systems, and a counterpart version of the application for mobile devices.
Users of the mobile devices provide data to and receive data through computer software applications executing on the mobile devices. A mobile device, therefore, is often a repository of several items of data. Some of the items of data are associated with computer software applications, while others are associated with the mobile device itself. In some situations, a mobile device can be a database that stores data that is neither associated with a computer software application that the mobile device executes or with the device itself. Several facilities are available to securely store data on a system such as a computer system or a mobile device. For example, a data encrypting software application executing on a system can encrypt and decrypt data stored on the system. The software application, in some situations, can request an input from a user to either encrypt or decrypt data (or both).
Mobile devices are configured such that a user of a mobile device can execute multiple computer software applications simultaneously. To enhance device useability from a user's perspective, the device can allow the user to switch between the software applications with minimum effort. For example, the device can implement functionalities that allow a user to invoke one application (such as a map application) using a user interface provided by another application (for example, an Internet browser). While a mobile device can implement data encrypting software applications to encrypt/decrypt data that is associated with a computer software application that is executing on the device, a useability of the device may be affected, for example, if the user's effort to switch between applications is increased by a need to provide input to the data encrypting application.